D3.235 - Trends in Sensitization to Preservatives and Epoxy Resins among occupationally exposed workers: A 31-Year Patch Test analysis from Tunisia

Contact allergies to preservatives and epoxy resins are increasingly recognized as occupational health concerns due to their widespread use in industrial and construction settings. However, long-term epidemiological data from North Africa are scarce. This study analyzes patch test results collected over a 31-year period in Tunisia to characterize temporal sensitization trends and identify high-risk occupations.

We conducted a retrospective descriptive study of 1,310 adult patients patch-tested over a 31-year period at the Dermato-Allergology Unit of the Occupational Medicine Department, CHU Farhat Hached, Sousse, Tunisia. Patch testing was performed using the Baseline Series (BSE), including preservatives (Kathon CG, paraben mix) and epoxy resin. Collected variables included year of testing, occupation, occupational exposure history, sensitization results, and etiological attribution. Temporal trends were analyzed by decade. High-risk occupations included plastics and composites workers and painters. Positive reactions were defined as ≥1+ according to international criteria. Chi-square tests and multivariable logistic regression were applied, with p<0.05 considered significant.

Among the 1,310 patients (mean age 45.2 ± 12.3 years; 62.5% men), approximately 80% were active workers. Sensitization to preservatives increased significantly over time, rising from 8.2% in the earliest decade to 16.4% in the most recent decade (p<0.01). Epoxy resin sensitization showed a marked increase from 3.1% to 7.8% across decades (p<0.001) and was highest among plastics and composites workers (11.9% of this subgroup; adjusted OR 3.2, 95% CI 2.1–4.8). Kathon CG was the most frequent preservative allergen (9.3% overall). Hands, particularly the dorsal surfaces, were the predominant sites of involvement (67.2% of epoxy-positive cases). Occupational etiology was retained in 48.6% of preservative and epoxy-related dermatitis, compared with 32.1% for other allergens (p<0.001).

Over three decades, sensitization to preservatives and epoxy resins increased substantially among Tunisian workers, disproportionately affecting those in plastics and composites occupations. The predominance of hand involvement highlights the need for strengthened preventive strategies, including exposure substitution, improved skin protection, and systematic patch testing in high-risk occupational settings.